The addition of a hydrazine compound to a silver halide photographic emulsion and a developing solution is known by disclosures such as U.S. Pat. No. 3,730,727 (the developing solution comprising ascorbic acid and hydrazine), U.S. Pat. No. 3,227,552 (hydrazine is used as the auxiliary developing agent for obtaining a direct positive color image), U.S. Pat. No. 3,386,831 (the .beta.-monophenylhydrazine of an aliphatic carboxylic acid is contained as a stabilizer for a silver halide photographic material), U.S. Pat. No. 2,419,975 and Mees, The Theory of Photographic Process, 3rd Ed. (1966), page 281.
Of the above, in particular, U.S. Pat. No. 2,419,975 discloses that a high contrast negative image can be obtained by the addition of a hydrazine compound.
U.S. Pat. No. 2,419,975 discloses that an extremely high contrast photographic characteristic of gamma (.gamma.) exceeding 10 can be obtained by adding a hydrazine compound to a silver chlorobromide emulsion to prepare a photographic material and developing the material with a developing solution having very high pH of 12.8. However, such a strongly alkaline developing solution having pH of almost 13 is prone to be air oxidized, unstable and cannot endure long term storage or usage.
Various contrivances have been attempted to develop a silver halide photographic material containing a hydrazine compound with a developing solution having pH as small as possible to obtain a high contrast image.
There are disclosed in JP-A-1-179939 and JP-A-1-179940 (the term "JP-A" as used herein refers to a "published unexamined Japanese patent application") the processing method of developing a photographic material containing a nucleating development accelerator having an adsorptive group onto silver halide emulsion grains as well as a nucleating agent having an adsorptive group with a developing solution having pH of 11.0 or less. However, the compound having an adsorptive group, when added to a silver halide emulsion in the amount exceeding a certain limit, impairs sensitivity, inhibits development, or hinders the functions of other useful adsorptive additives, therefore, the amount used is limited and sufficient high contrast cannot be manifested.
JP-A-60-140340 discloses that high contrast is increased by the addition of amines to a silver halide photographic material. However, sufficient high contrast cannot be obtained when developing with the developing solution having pH of less than 11.0.
JP-A-56-106244 discloses the addition of an amino compound to the developing solution having pH of from 10 to 12 to accelerate contrast. However, when amines are added to a developing solution, the solution gives out a bad odor, the apparatus used is stained with the adhesion of smudges, further there arises a problem of the environmental pollution due to the waste solution. Therefore, it is desired to incorporate amines into a photographic material but sufficient performance cannot be obtained when added to a photographic material.
Also, gelatin is generally used as a binder for hydrophilic colloid layers constituting a silver halide photographic material, but such hydrophilic colloid layers are liable to expand and contract to humidity and temperature changes and are fragile under a low humid atmosphere.
For improving such drawbacks, a polymer latex is incorporated into hydrophilic colloid layers such as a silver halide emulsion layer, an interlayer, a protective layer and a backing layer.
For example, there are disclosed in U.S. Pat. Nos. 2,763,625, 2,852,382, JP-A-62-115152, JP-A-5-66512, JP-A-5-80449, JP-B-60-15935, JP-B-4-64058 and JP-B-5-45014 (the term "JP-B" as used herein refers to an "examined Japanese patent publication") the incorporation of a polymer latex comprising various monomers such as alkyl acrylate and alkyl methacrylate and so on into hydrophilic colloid layers. Further, JP-B-45-5819, JP-B-46-22507 and JP-A-50-73625 disclose that the strength of the gelatin film containing a latex at a wet state can be improved by the incorporation of a polymer latex obtained by copolymerizing a monomer having an active methylene group with a monomer such as alkyl acrylate into the gelatin film.
However, in the case where a hydrazine derivative is used for obtaining a high contrast image, the photographic material containing such a latex has some problems such that gradation of images become soft and the film strength at a wet state is not sufficient, and the improvement of these problems has been desired.